Boyce Thompson Arboretum

Visitors observe Demonstration
Garden rattlesnake "dance"

Horticulturist Steve Carter and about a half-dozen visitors
who were fortunate enough to be exploring the Demonstration Garden on the
morning of Sept. 7 witnessed two sizable western diamondback rattlesnakes
engaging in a ritualized behavior often called a "dance." Was it
a courtship ritual between snakes of opposite sex? Combat?

You
can see by Steve's photos both rattlers were nearly identical in size at just
more than three-feet long. Was this a competion pitting one male against another?
For a definitive answer we asked Marty Feldner of reptilesofaz.com
Here's his answer.

"The 'snake dance' you witnessed was to determine dominance between two
males. This behavior has been recorded in a number of species of rattlesnake
but is most frequently witnessed in diamondbacks. One reason it is most frequently
witnessed in diamondbacks is the bi-phasic breeding season: Diamondbacks have
both a spring and a late summer/fall breeding season - other rattlesnake species
have only a single breeding season. During these times when males encounter
one another they will raise the forward portion of their body off the ground
and engage one another. Usually, the larger male will force the smaller male
to the ground - sometimes quite forcefully.If
the two snakes are of equal size the interaction can last a long time if the
snakes want to "fight" it out, or can end rather quickly as the
snakes realize they are equally matched.
The name for the snake dance behavior is "combat." The male who
wins may win breeding rights if a female is present or nearby. The male who
loses has a physiological response which will result in a rise of stress hormones
and generally will seek refuge, losing interest in breeding.
Some further info...You asked if there was a possible territorial dispute.
Snakes have home ranges but not territories. Territoriality implies that an
organism will guard and defend its home range against other members of its
species. Snakes
don't defend their home ranges. Only in times of breeding do we witness interactions
to determine dominance amongst snakes.
Courtship in rattlesnakes is much more subtle than the combat display you
witnessed. When a male encounters a female he will usually position himself
close to the female - sometimes the snakes are coiled and sometimes not. The
interested male will generally lay his head on the female, often twitching
or jerking his head in a behavior termed "chin rubbing." Females
may be receptive and copulate or may be unreceptive and try to hide their
head.